xref: /illumos-gate/usr/src/uts/common/sys/mutex.h (revision e603b7d4)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #ifndef _SYS_MUTEX_H
27 #define	_SYS_MUTEX_H
28 
29 #pragma ident	"%Z%%M%	%I%	%E% SMI"
30 
31 #ifndef	_ASM
32 #include <sys/types.h>
33 #endif
34 
35 #ifdef	__cplusplus
36 extern "C" {
37 #endif
38 
39 #ifndef	_ASM
40 
41 /*
42  * Public interface to mutual exclusion locks.  See mutex(9F) for details.
43  *
44  * The basic mutex type is MUTEX_ADAPTIVE, which is expected to be used
45  * in almost all of the kernel.  MUTEX_SPIN provides interrupt blocking
46  * and must be used in interrupt handlers above LOCK_LEVEL.  The iblock
47  * cookie argument to mutex_init() encodes the interrupt level to block.
48  * The iblock cookie must be NULL for adaptive locks.
49  *
50  * MUTEX_DEFAULT is the type usually specified (except in drivers) to
51  * mutex_init().  It is identical to MUTEX_ADAPTIVE.
52  *
53  * MUTEX_DRIVER is always used by drivers.  mutex_init() converts this to
54  * either MUTEX_ADAPTIVE or MUTEX_SPIN depending on the iblock cookie.
55  *
56  * Mutex statistics can be gathered on the fly, without rebooting or
57  * recompiling the kernel, via the lockstat driver (lockstat(7D)).
58  */
59 typedef enum {
60 	MUTEX_ADAPTIVE = 0,	/* spin if owner is running, otherwise block */
61 	MUTEX_SPIN = 1,		/* block interrupts and spin */
62 	MUTEX_DRIVER = 4,	/* driver (DDI) mutex */
63 	MUTEX_DEFAULT = 6	/* kernel default mutex */
64 } kmutex_type_t;
65 
66 typedef struct mutex {
67 #ifdef _LP64
68 	void	*_opaque[1];
69 #else
70 	void	*_opaque[2];
71 #endif
72 } kmutex_t;
73 
74 #ifdef _KERNEL
75 
76 #define	MUTEX_HELD(x)		(mutex_owned(x))
77 #define	MUTEX_NOT_HELD(x)	(!mutex_owned(x) || panicstr)
78 
79 extern	void	mutex_init(kmutex_t *, char *, kmutex_type_t, void *);
80 extern	void	mutex_destroy(kmutex_t *);
81 extern	void	mutex_enter(kmutex_t *);
82 extern	int	mutex_tryenter(kmutex_t *);
83 extern	void	mutex_exit(kmutex_t *);
84 extern	int	mutex_owned(kmutex_t *);
85 extern	struct _kthread *mutex_owner(kmutex_t *);
86 extern	void	plat_lock_delay(int *);
87 
88 #endif	/* _KERNEL */
89 
90 #endif	/* _ASM */
91 
92 #ifdef	__cplusplus
93 }
94 #endif
95 
96 #endif	/* _SYS_MUTEX_H */
97